Hoffman Amplifiers Tube Amplifier Forum
Amp Stuff => Tube Amp Building - Tweaks - Repairs => Topic started by: oldhippy on September 29, 2010, 06:59:00 pm
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Hey guys
I've got the chance at a bucketload (or rather old Hammond full) of 12AU7 labeled "made in USA" and "C.G. CON-something" incomplete print, green ink... are they worth the gas to go get them? It's a thirty mile trip one way :-) Would they be RCA's? Are there any sites out there with old tube ID information? I haven't been able to find much. Any thoughts would be appreciated...
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Probably OEM tubes for C.G. Conn Ltd., aka Conn Instruments, a large manufacturer of musical instruments, including some nice organs. Saw a few of their 12AU7s, all were manufactured by Sylvania - which happened to use green ink most of the time. Well worth a drive IMO.
(http://tctubes.com/images/products/detail/391_12AU7_SYL_PR_800.jpg)
From the TC Tubes web site.
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All the RCA preamp tubes I have found in Hammonds have the orange printing on them with the Hammond logo overstamped.
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Used AU7's are only worth about 2 or 3 bucks ea. Now if they're gutting the Hammond (which makes me sad), the amp chassis is the thang to have. The old transformers make simply splendid geetar amps, especially (IMO) the reverb amps.
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+1 if your getting the whole organ or at least more parts from it.
12AU7's? good tubes, but hardly used in guitar amps. AWeSOME in a hi fi amp.
If you just need a few good AU7's I got a bucket full of 1958 Amperex bugle boy I could send a couple for a worthy cause.
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Well it's been a while since I looked in my bucket.
maybe 25 or so left out of the original 49 pulled.
You know what? how much you gonna spend on gas? got someone you want to spend some time with on a leisurely trip? you going to end up some where and talk vacuum tubes?
go get em. have fun add to your collection.
who knows, you might find just the right one for that special lo watt amp
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thanks for the feedback, guys. Exactly as pictured, thank you. FWIW, I made further inquiry and found out the tubes are in an old Conn organ (not sure why he thought it was a Hammond, didn't ask). THAT would account for the CONN on the tubes, huh? :-)Anyway, if I want the tubes, I have to take the whole thing...hmmm...maybe it'll have a decent amp in it, I've never seen one. Here I go...I'm not going to tell my wife...where AM I going to put it? lol thanks again...peace
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Go get it!
Love the Cleland speakers from Conn's.
Lot of great shielded wire and other goodies to including beefy trannys.
Last Conn I got I had a quad of 7858 which I e-bayed for $95
Oh and I got a weird coke bottle 2050 which is a vacuum tube triac used to turn on and off the Leslie
OH! and a 1 speed leslie that I ended up putting a DC motor on and used the expression pedal to control a the DC power supply to make a variable speed stand alone Leslie.
Boy I love old organs.
If you take a pair of wire cutters, cordless screw driver, hammer and maybe a pair of pliers and a crescent wrench you can fit in in the trunk of a sedan.
bring a coffee can too LOTS of good hardware.
Ray
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Conns typically have a very nice, clean chassis, oblong, not square, that's pretty right on for an amp build. Good iron, too. Go look on ebay for "Conn" and you'll see what I mean. You may have to plug some holes or move a tranny around, and the nine-pin tubes utilze wafer-type sockets which I wouldn't reuse, but they are more than decent raw material.
http://cgi.ebay.com/Vintage-Conn-2-Channel-7868-12ax7-Tube-Amplifier-DK6026-/290474418589?pt=Vintage_Electronics_R2&hash=item43a19fe19d
http://cgi.ebay.com/Vintage-Conn-2-Channel-6L6-6V6-12au7-7199Tube-Amplifier-/290471561338?pt=Vintage_Electronics_R2&hash=item43a174487a
*Some* of the output trannies appear a tad smallish (eg; no end bells) but overall, very decent platforms.
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Ray wish I knew about your bucket 2 days ago as I have been trying to make the 12AU7's work as 1000w halogens in a firefly and have been unsuccessful. They can get very bright but don't last but more than 2 seconds thus far. But if I had a bucket full I could have run some more experiments. LOL
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It's OK to kill a Conn, just leave the tonewheel Hammonds alone. I've got a Hammond, and just got my modified Leslie speaker working with it.
The "Good" Hammonds have very few 12AU7's. Conn's, Lowrey's, Baldwins are loaded with them as they used oscillators to make their tones as opposed to the Hammond which used the electromechanical "ToneWheel". Thus Hammonds have far fewer tubes than other of their contemporary electric theatre/church organs.
12AU7 has to be one of the most common tubes out there. I think the only tube that I have more of is 5U4 (or 12AX4 as I can't find a use for it at all) I've used them in home audio for Phonograph preamps. I've also made a basic mic preamp with them. They don't really have the gain we are looking to make a pickup signal go into overload. They are a good choice to try to clean up an amp that has several gain stages....
j.
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It's OK to kill a Conn, just leave the tonewheel Hammonds alone.
+1
if you find a Hammond, leave it where it is and send me the address I'll go get it for you.
Ray
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If you like a great sparkly clean sound put a 12au7 in the first socket of a 5e3 (or probably a number of tweed amps).
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Are the trannys in a Conn any good for guitar amp ?
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I haven't hacked up a Conn organ but would do it in a second. The best sounding amp I've had a hand in used iron from a Baldwin organ. One shouldn't hack a Hammond until the tone generator is done for, which is much harder to do than you'd think. Hammond organs are almost musician proof.
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Are the trannys in a Conn any good for guitar amp ?
Depends! LOL
What Amp you looking to build and what PT you have.
Generally speaking? Heck Yes.
I've built lots of amps around Iron I have lying around. The guys here have helped me thru my design errors LOTS.
I still haven't gotten so good at ASKING before I BUILD.
Ray
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Many of the old Conns used Foster and Schumacher transformers, and both are very good quality. Their construction and parts choices were pretty good too. The old Thomas organs often used the molded blue Mallory caps. Old organs are your friends if you have the time to mess around with them....
greg
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One shouldn't hack a Hammond until the tone generator is done for, which is much harder to do than you'd think. Hammond organs are almost musician proof.
Indeed, and I've even resurrected a tone generator before. They were so well made, but if you look at a price list from back in the day they'd sell for somewhere between a new fully-loaded Buick and a Cadillac at the time, with some models even higher. OR half the price of a brand new "Levitt" Ranch Style home. For that kind of money, they had to be good. To think, it was the cheaper alternative to a pipe organ...
j.